The present invention relates to a casing of a trunk piston internal combustion engine having a cylinder head, cylinder head cover block, oil sump regions and bearing devices for the crankshaft and camshaft.
In known casings, the cylinder block and crankcase are usually an integral part. It is also known to configure the cylinder head and cylinder block as an integral casting, with the cooling water spaces being formed by using soluble cores in the casting. The individual parts are bolted together to form a closed engine casing.
In addition, the welding together of individual separately manufactured parts of the engine casing is also already known, as shown in U.S. Pat. No. 2,975,778 and DE-GM 66 10 188. The structure of this known welded engine casing, however, is extremely complicated. The same problem applies, in principle, to the casing shown in U.S. Pat. No. 2,975,778 in which additional bolted connections are also necessary.
Accordingly, the present invention solves the problem of being able to manufacture the engine casing in a particularly low-cost manner from casings which can, overall, be assembled in as simple a manner as possible. In particular, complicated castings which can only be produced by the use of lost cores are now unnecessary.
This problem has been solved in accordance with the present invention by an engine casing in which the cylinder block region, together with a part of the cylinder head closing each of the individual cylinder spaces at the combustion space end, is a common engine block casting, which has open hollow spaces manufactured without the use of lost cores and is open in the direction of the cylinder axis without an undercut portion, at least at one end thereof. The hollow spaces are closed by parts welded onto both axial ends to create a closed continuous water jacket.
The material of the engine casing should, in particular, be a light metal, preferably aluminum, which is cast by a vacuum diecasting method.